/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTLIMIT or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.model.mission;

import javax.xml.stream.XMLStreamException;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.io.FreeColXMLWriter;
import net.sf.freecol.common.model.Ability;
import net.sf.freecol.common.model.Game;
import net.sf.freecol.common.model.Specification;
import net.sf.freecol.common.model.TileImprovement;
import net.sf.freecol.common.model.Unit;

import static net.sf.freecol.common.util.CollectionUtils.*;

import org.w3c.dom.Element;


/**
 * The ImprovementMission causes a Unit to add a TileImprovement to a
 * particular Tile.
 */
public class ImprovementMission extends AbstractMission
{

    /**
     * The improvement of this Mission.
     */
    private TileImprovement improvement;


    /**
     * Creates a new <code>ImprovementMission</code> instance.
     *
     * @param game a <code>Game</code> value
     */
    public ImprovementMission( Game game )
    {
        super( game );
    }

    /**
     * Creates a new <code>ImprovementMission</code> instance.
     *
     * @param game a <code>Game</code> value
     * @param xr a <code>FreeColXMLReader</code> value
     * @exception XMLStreamException if an error occurs
     */
    public ImprovementMission( Game game,
                               FreeColXMLReader xr ) throws XMLStreamException
    {
        super( game, xr );
    }

    /**
     * Creates a new <code>ImprovementMission</code> instance.
     *
     * @param game a <code>Game</code> value
     * @param e an <code>Element</code> value
     */
    public ImprovementMission( Game game, Element e )
    {
        super( game, e );
        readFromXMLElement( e );
    }

    /**
     * Creates a new <code>ImprovementMission</code> instance.
     *
     * @param game a <code>Game</code> value
     * @param id The object identifier.
     */
    public ImprovementMission( Game game, String id )
    {
        super( game, id );
    }

    /**
     * Get the <code>Improvement</code> value.
     *
     * @return an <code>TileImprovement</code> value
     */
    public final TileImprovement getImprovement( )
    {
        return improvement;
    }

    /**
     * Set the <code>Improvement</code> value.
     *
     * @param newImprovement The new Improvement value.
     */
    public final void setImprovement( final TileImprovement newImprovement )
    {
        this.improvement = newImprovement;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public MissionState doMission( )
    {
        // FIXME: get rid of magic numbers: either add a pioneerWork
        // attribute to UnitType, or introduce an expertRole ability
        // and add the work to the Role definition
        int work = getUnit( ).hasAbility( Ability.EXPERT_PIONEER ) ? 2 : 1;
        setTurnCount( getTurnCount( ) - work );
        getUnit( ).setMovesLeft( 0 );
        return ( getTurnCount( ) <= 0 )
                ? MissionState.COMPLETED : MissionState.OK;
    }


    /**
     * Returns true if the mission is still valid.
     *
     * @return a <code>boolean</code> value
     */
    @Override
    public boolean isValid( )
    {
        return super.isValid( )
                && improvement != null
                && improvement.isWorkerAllowed( getUnit( ) );
    }

    /**
     * Returns true if the given Unit is allowed to build at least one
     * TileImprovementType.
     *
     * @param unit an <code>Unit</code> value
     * @return false
     */
    public static boolean isValidFor( Unit unit )
    {
        final Specification spec = unit.getGame( ).getSpecification( );
        return any( spec.getTileImprovementTypeList( ),
                    ti -> ti.isWorkerAllowed( unit ) );
    }


    // Serialization.

    private static final String IMPROVEMENT_TAG = "improvement";


    /**
     * {@inheritDoc}
     */
    @Override
    protected void writeAttributes( FreeColXMLWriter xw ) throws XMLStreamException
    {
        super.writeAttributes( xw );

        xw.writeAttribute( IMPROVEMENT_TAG, improvement );
    }


    /**
     * {@inheritDoc}
     */
    @Override
    protected void readAttributes( FreeColXMLReader xr ) throws XMLStreamException
    {
        super.readAttributes( xr );

        improvement = xr.makeFreeColGameObject( getGame( ), IMPROVEMENT_TAG,
                                                TileImprovement.class, true );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getXMLTagName( ) { return getXMLElementTagName( ); }

    /**
     * Gets the tag name of the root element representing this object.
     *
     * @return "improvementMission"
     */
    public static String getXMLElementTagName( )
    {
        return "improvementMission";
    }


}
